The present invention relates to a compressor which compresses fluids such as refrigerants or air and discharges the compressed fluids.
Conventionally, for example, a refrigerator has employed a system of compressing a refrigerant by using a compressor and circulating the compressed refrigerant in a circuit. As such compressor systems in this case, there are available a rotary compressor called a rotary type compressor (e.g., see Japanese Patent Application Laid-Open No. 5-99172 (Document 1)), a scroll compressor, a screw compressor and the like.
The rotary compressor has advantages that a structure is relatively simple and production costs are low, but there is a problem of increases in vibration and torque fluctuation. In the scroll compressor or the screw compressor, there is a problem of high costs caused by bad workability while torque fluctuation is small.
Thus, there has been developed a system which disposes a swash plate as a rotary compression member in a cylinder and partitions compression spaces constituted below and above the swash plate by a vane to compress fluids (e.g., PCT No. 2003-532008 (Document 2)). According to the compressor of this system, there is an advantage of constituting a compressor which is relatively simple in structure and small in vibration.
However, in the case of the structure of the Patent Document 2, since a high pressure chamber and a low pressure chamber are adjacent to each other below and above the compression member (swash plate) in the entire region of the cylinder, a difference between high and low pressures is enlarged, and refrigerant leakage causes a problem of efficiency deterioration.
Especially, there have occurred problems that the refrigerant in the compression space formed in a surface of the compression member on a driving element side easily leaks between a rotary shaft and a bearing of the rotary shaft, and degradation of performance of the compressor is caused.
Furthermore, in the conventional constitution in which the compression spaces are constituted above and below the compression member, back pressures of the compression spaces cannot be controlled. Therefore, friction is generated between the compression member and the vane which abuts on the compression member or a member disposed facing the compression member, and the compression member is remarkably worn. Therefore, there has occurred a problem that durability is deteriorated, and a mechanical loss increases.